BETH!!! ICH life cycle question

jafrancis

jafrancis

Member
You say there are 4 stages:1. Trophont stage: seen as the mature parasite attached to the fish. cycle timeframe: aprrox 7 days
2. Tomont stage: swims in the water column for several hours until it can find a place in the aquarium to settle. It will then attach itself to a surface in the aquarium.
cycle timeframe: several hours
3. Tomite stage: products of the parasite reproducing. They become free-swimming in the aquarium as theronts.
cycle timeframe: approx 4 days
4. Theront stage: free-swimming protozoans that must locate a host fish or die trying.
cycle timeframe: several hours
So in a tank with no fish there is no Trophont stage possible and therefore ICH must be in one of the last 3 stages, correct. So without a host, shouldn't the ICH be dead in: Several Hours + approx 4 days + Several hours???????
So why the need to keep the tank empty for 4-6 weeks as some recommend?????
According to the info provided, 5 days should suffice in a tank with no fish.......
PLEASE explain the reasoning behind the longer waiting period as I feel that I must be missing something!!!!
THANKS!!!!!
 
beth

beth

Administrator
Staff member
Assuming that every parasite is in the same life cycle at exactly the same time? :thinking: How likely is that?
 
jafrancis

jafrancis

Member
But if there are no fish in the tank, then the longest period of time that they could possible live will be about 4 days + a few hours correct???? Some may be in further stages, but that would mean that they would die sooner correct.
My reasoning is that once they hit the 4th stage, if they can't find a host, they will die.
So lets say you have a fish with visable ICH. They are in the Trophont stage. You remove all your fish from the tank at this point. Yes there will be some ICH in the various stages. But lets say some of the ICH falls off the fish seconds before you remove all your fish.
The ones that just came off the fish will be the longest lived as it will JUST be starting the Tomont stage. Therefore, it could only survive up to 4+ days......
NOT ARGUING....JUST TRYING TO FULLY UNDERSTAND!!!!

Your attent student,
J
 
jafrancis

jafrancis

Member
Decided to look it up in some Parisitology texts that I have (from Vet school).....This is what I found....
Treatment of Cryptocaryon irritans in Aquaria
By: Dr. Harry W. Dickerson (Harry W. Dickerson, B.V.Sc. Ph.D., is Associate Professor at the University of Georgia College of Veterinary Medicine, Athens, Georgia.)
Life Cycle
It spends five to seven days (at 24 to 27°C) feeding and growing in the skin and gills. The parasite at this stage is called a trophont.
When the parasite reaches maturity it leaves the fish and enters the water as a large single cell called a tomont. The parasite swims for 12 to 18 hours until a sticky, opaque cyst wall is secreted which allows it to attach to substrates such as rock, coral, or glass.
The cells divide within each cyst to produce up to 200 daughter parasites called tomites. This multiplication process takes anywhere from 3 to 28 days (Colorni 1985).
These free-swimming cells are the infective form of the parasite called theronts. They survive for only a few hours unless they find a host. When the theronts encounter a fish, they burrow into skin and gill tissue where they begin to grow, thus completing the life cycle.
1. Colorni, A. 1985. Aspects of the biology of Cryptocaryon irritans, and hyposalinity as a control measure in cultured gilt-head sea bream Sparus aurata. Dis. Aquat. Org. 1:19-22.
2. Colorni, A. and A. Diamant. 1993. Ultrastructural features of Cryptocaryon irritans, a ciliate parasite of marine fish. Euro. J. Protistology. 29:425-434.
So the TOMITE STAGE CAN LAST FROM 3-28 DAYS!!!!
So a complete life cycle of ICH is approx. 9-36 DAYS!!!! Therefore a tank should be left empty (without a fish host) atleast 29 days to allow for death of ALL of the ICH parasites.
 
jafrancis

jafrancis

Member
The longest recorded period of time for tomonts to hatch is 72 days (Colorni & Burgess, 1997). The life cycle of Cryptocaryon irritans is temperature dependent so it is highly unlikely for such an extended period to occur in a tropical aquarium.
Colorni, A. & Burgess, P.J. “Cryptocaryon irritans Brown 1951, the Cause of White Spot Disease in Marine Fish: an Update.” Aquarium Sciences and Conservation, 1, 217-238, 1997.
 
beth

beth

Administrator
Staff member
The textbooks and science will agree that the life-cycle is sufficiently disrupted in the absence of fish to kill off the parasite within a week, however, the reality is that there is enough anecdotal evidence that contradicts this. 3 weeks is good measure, and worth the wait, IMO.
 
jafrancis

jafrancis

Member
From what I have read, I will wait atleast 30 days to allow for the possibility of the Tomite stage lasting 3-28 days.
Thanks for your help Beth!!!
 
fishtk75

fishtk75

Member
I was tolded by all here and others to wait 6 weeks min to 8 weeks to kill it all both in my HYPO QT and my fishless main tank they said to be safe then start all over again..
 
sebranek

sebranek

New Member
I would not agree that 3 weeks is enough. I can see the cyst stage in my tank and it has been 50 days and 7 water changes since I removed the fish.
 
1journeyman

1journeyman

Active Member
Originally Posted by sebranek
I would not agree that 3 weeks is enough. I can see the cyst stage in my tank and it has been 50 days and 7 water changes since I removed the fish.
This is a pretty old post; but are you sure you are seeing the cysts? They are pretty small....
 
aquaknight

aquaknight

Active Member
I will back him up, I saw cysts on my 125's glass well after a month. Granted, I had a severe case that claimed over 8 fish of the course of 5 days, but the glass was covered will tomonts for a while.
8 weeks is my flat recommedation, though as close to, or over, 72days if possible.
 
sebranek

sebranek

New Member
I am sure I can see them and that it is the ick cysts. I lost no fish thank God.
They started out by the hundreds. And have slowly tapered off to only a few.
I wish I had the equipment to take a picture because I believe many people end up suffering this same fate by taking chances and not Qt.
 
dancoolr

dancoolr

Member
Hello, I dont have enough space to put my fish in qt tanks. What will happen if I leave the infected but hopefully getting better fish ( using garlic) in the tank and no add any fish and continue to do water changes in the tank for 4 weeks.
 
waterlogged

waterlogged

Member
Originally Posted by 1journeyman
This is a pretty old post; but are you sure you are seeing the cysts? They are pretty small....
What do the cysts look like?
 
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